M13 Hercules Cluster
M13 is magnificent sight in a good scope, like swarm of insects. It was discovered by Edmond Halley in 1714, and is now known to be 25,100 light-years away from Earth. With an apparent magnitude of 5.8, it is just visible with the naked eye on a very clear night. If you look closely, you can see towards the lower left NGC 6207, a 12th magnitude edge-on galaxy that lies 28 arc minutes directly north east. Also an even smaller galaxy, IC 4617, can be seen halfway between NGC 6207 and M13, just left of the globular cluster's center.
M13 is about 145 light-years in diameter, with several hundred thousand stars, the brightest of which is the variable star V11 with an apparent magnitude of 11.95.
Orion Optics UK AG16 Astrograph: SBIG 11000 CM: Titan Mount, Pixinsight and Photoshop CS5.5
24 x 3 minutes
Data capture 14th October 2011, reprocess April 2013